ADC Demo

adc.c

/////////////////////////////////////////////////////////////////////////////
// HC12 Program:  Demo 5 - ADC
// Processor:     MC9S12XDP512
// Bus Speed:     20 MHz (Requires Active PLL)
// Author:        AJ Armstrong
// Details:       Demo of voltage measurement
// Date:          Oct 2023
// Revision History :
/////////////////////////////////////////////////////////////////////////////

#include <stdio.h>      // For sprintf, etc
#include <ctype.h>      // For character utilities
#include <string.h>     // Various string utilities
#include <hidef.h>      // Common defines and macros
#include "derivative.h" // Derivative-specific definitions
#include "pll.h"        // Phase-locked loop clock control
#include "swled.h"      // GPIO switches and LEDs
#include "timer.h"      // Enhanced capture timer
#include "rti.h"        // Realtime interrupts
#include "segs.h"       // 7-Segment Displays
#include "lcd.h"        // LCD Display
#include "sci.h"        // Serial communications interface (EIA/TIA-232)

/////////////////////////////////////////////////////////////////////////////
// Local Prototypes
/////////////////////////////////////////////////////////////////////////////
void blinky(void); //Toggle yellow led
void displayVolts(void); // Update LCD with most recent voltages.
/////////////////////////////////////////////////////////////////////////////
// Global Variables
/////////////////////////////////////////////////////////////////////////////

volatile uint ADVal[8] = {0};

/////////////////////////////////////////////////////////////////////////////
// Constants
/////////////////////////////////////////////////////////////////////////////

/////////////////////////////////////////////////////////////////////////////
// Main Entry
/////////////////////////////////////////////////////////////////////////////

void main(void)
{
  _DISABLE_COP(); //No watchdog

  /////////////////////////////////////////////////////////////////////////////
  // One-Time Initializations
  /////////////////////////////////////////////////////////////////////////////
  PLL_To20MHz(); // Configure the main clock to 20 MHz (implications for timers)
  SWL_Init();    // Standard initialization for switches and LEDs
  SEG_Init();    // Standard initializaton for 7-seg displays
  RTI_Init();    // Initialize RTI timer

  /////////////////////////////////////////////////////////////////////////////
  // Initialize ADC
  /////////////////////////////////////////////////////////////////////////////
  // Power up - Fast flag clear, Enable interrupts
  ATD0CTL2 = ATD0CTL2_ADPU_MASK | ATD0CTL2_AFFC_MASK | ATD0CTL2_ASCIE_MASK;
  
  // I need to wait at least 20 uSec for ADC to power up and stabilize
  // LCD initialization takes like, forever, so I moved it here.
  LCD_Init();    // Set up LCD (takes a while)

  // Convert all 8 pins, finish then freeze
  ATD0CTL3 = ATD0CTL3_S8C_MASK | ATD0CTL3_FRZ1_MASK;
  // 10-bit resolution, 4 A/D coversion clock periods, 
  // prescaler to 10 -> 2MHZ ADC-Clock (w/ 20 MHz bus)
  ATD0CTL4 = ATD0CTL4_SMP0 | ATD0CTL4_PRS2_MASK;
  // Wrap at 5.
  ATD0CTL0 = 5;
  //And set it to continuously convert, unsigned, right justified, multiple chans
  ATD0CTL5 = ATD0CTL5_DJM_MASK | ATD0CTL5_SCAN_MASK | ATD0CTL5_MULT_MASK;


  /////////////////////////////////////////////////////////////////////////////
  // Main Program Loop
  /////////////////////////////////////////////////////////////////////////////

  EnableInterrupts; // Ensure our board will respond to interrupt signals.

  LCD_StringRC(0, 0, "ADC Demo");
  RTI_RegisterEvent(0,blinky,100); //Das blinkenlichten
  RTI_RegisterEvent(3,displayVolts,250); //Quarter second updates

  for (;;)
  {
    //Not going to WAI, because ADC interrupts happen fast
  }
}
/////////////////////////////////////////////////////////////////////////////
// Functions
/////////////////////////////////////////////////////////////////////////////
void blinky(void){SWL_ToggleLEDs(eYellow);} //Toggle yellow led

void displayVolts(void) //Update display of ADC voltages
{
    char szBuff[256] = ""; // Buffer for creating strings
      //Channel 5, at Pin 77
      SEG_16H(ADVal[5],0); //Top segs
      sprintf(szBuff, "Voltage 5: %5.3f V", ADVal[5]/1023.0*5.0);
      LCD_StringRC(2, 2, szBuff); 
      //Channel 0, at Pin 67
      SEG_16H(ADVal[0],1); //Bottom segs
      sprintf(szBuff, "Voltage 0: %5.3f V", ADVal[0]/1023.0*5.0);
      LCD_StringRC(3, 2, szBuff);
}

/////////////////////////////////////////////////////////////////////////////
// Interrupt Service Routines
/////////////////////////////////////////////////////////////////////////////

// ISR for ADC 0
interrupt VectorNumber_Vatd0 void INT_AD0(void)
{
  // read channel values
  ADVal[0] = ATD0DR0;
  //ADVal[1] = ATD0DR1;
  //ADVal[2] = ATD0DR2;
  //ADVal[3] = ATD0DR3;
  //ADVal[4] = ATD0DR4;
  ADVal[5] = ATD0DR5;
  //ADVal[6] = ATD0DR6;
  //ADVal[7] = ATD0DR7;
}